Method for treatment of microorganisms

Abstract

A method for treating a microorganism which comprises chemically treating the microorganism with at least one agent selected from the group consisting of an acid, an alkali and a hydrophilic solvent and mechanically rupturing the cell membrane of the resulting chemically treated microorganism using a sand grinder or a three roll mill is disclosed.

I claim: 
     
       1. A method for producing a yeast extract comprising nucleic acids and related substances which comprises chemically treating microorganisms with an alkali to extract material from said cells while substantially leaving within said cells protein contained within said cells, separating the thus treated microorganism cells from a waste liquor and adjusting said waste liquor to a pH of from 1 to 7, said alkali treatment being carried out by autolyzing the microorganisms with alkali at a pH of 7.0 to 10.5 and at a temperature of 25° to 65°C for a period of from 16 hours to 10 minutes or by treatment with alkali at a pH of from 10.5 to 12.9 at a temperature below 30°C for a period of about 4 minutes to 6 hours. 
     
     
       2. The method according to claim 1, which comprises adjusting said waste liquor to a pH from 4.5 to 6.5, adding activated carbon to said waste liquor to absorb nucleic acids and substances related thereto, and filtering the waste liquor to remove said activated carbon to obtain a yeast extract.